A134372 a(n) = ((2n)!)^2.

1, 4, 576, 518400, 1625702400, 13168189440000, 229442532802560000, 7600054456551997440000, 437763136697395052544000000, 40990389067797283140009984000000, 5919012181389927685417441689600000000

Offset

0,2

Links

Table of n, a(n) for n=0..10.

Formula

From Amiram Eldar, Nov 16 2020: (Start)

Sum_{n>=0} 1/a(n) = A334379.

Sum_{n>=0} (-1)^n/a(n) = A334632. (End)

Mathematica

Table[((2n)!)^(2), {n, 0, 10}]
((2*Range[0, 20])!)^2 (* Harvey P. Dale, Jul 14 2011 *)

Prog

(PARI) a(n) = ((2*n)!)^2; \\ Michel Marcus, Nov 16 2020

Crossrefs

Cf. A000142, A001044, A000442, A036740, A010050, A134366, A134367, A134368, A134369, A134371, A134374, A134375, A334379, A334632.

Sequence in context: A274470 A282196 A114764 * A177926 A241095 A343474

Adjacent sequences: A134369 A134370 A134371 * A134373 A134374 A134375

Keyword

nonn

Author

Artur Jasinski, Oct 22 2007

Status

approved